cat with hurt leg

hello my friend has a cat he is 2yrs old and he comes and goes when he wants he came home thursday with a hurt leg. they checked it thinking he had a sticker in his paw and now today his whole leg is swollen and it hurts him if you touch it my friend is taking him to the vet a 3pm today I was wondering how you tell if it is broken i dont think you can. and is there anything my friend can give him for the pain. i told my friend that she might just have to wait for the vet to look at him and give him meds. any info would help thanks